Ask them about the millions of japanese people spread across the western pacific and other asian countries who were deported back to Japan by the US. The simple answer is that displacements of entire people as a result of decolonization was happening and was a worldwide phenomenon at the time which unfortunately the Soviet Union was caught up in. Just take a look at whole countries such as Pakistan/India Malaysia/Singapore, Czech/Slovakia or even the whole African continent which is still stuck in perpetual war with each over. All you need to know is the Soviet’s solutions were 100x more humane than any western counterpact that had to deal with the same issue.